Brake-control mechanism



March 3, 1931. JACKSON 1,794,461

BRAKE CONTROL MECHANI SM Filed April 17, 1929 K5 Z9 Z7 1? 18 Z4: Z5

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INVENTOR- 1 MAUNSELL B. TACKSQN.

Wm WM.

BY ATTOQNEYS.

Patented Mar. 3, 1931 UNITED -STATES PATENT' OFFICE munsnnn .B. .moxson, or" rononro, oN'rARIo, cums-- BRflKE-CONTROL MECHANISM Application filed April 17, 19a, Serial No. 355,867, and in Qreat Britain February 20, 1929.

' This invention relates to brakev control mechanism and its object is to provide a con trol mechanism for motorcar brakes which will operate the brakes without requiring considerable muscular effort on the part 'of the driver and will preferably also, have a modicum of automatic action especially when the engine of the car stalls.

With this obj ectin view the invention consists'in the construction, combination and arrangement of parts hereinafter described and more particularly pointedout in the appended claims.

Y Referring now to theaccompanying drawings, which illustrate, by way of example,- one convenient embodiment of the invention:

Figure 1 is a partial longitudinal section of the improved brake operating mechanism showing the operating lever inthe position it occu ies when the fluidpressure is holding the bra es ofi. Figure lalso shows the latching position of the manually operated releasin lever. a

igure 2 is a partial longitudinal section of the brake operating mechanism showing the operating lever in brake applying po sition. 4

Figure 3 is a diagrammatic elevation, indicating the brake and pressure fluid .con-

' nections.

In the illustrated example the numeral 1 1 indicates a cylinder attached in any suitable manner to a source of fluid under pressure. For example, the cylinder may be connected by a pipe 2 to the oil pump 3 of the en e 4-. 'A piston 5 is slida ly mounted in cy 'nder 1. A piston rod 6 is fastened to the piston-5 by a nut 7 and carries collar 8. A spring 9 tends to 'force piston 5 to the left as shown in Figure 2,-in which position rod 6 applies the brake 10:01 the car; Spring 9 is shown in cylinder 1 and acting directly on piston rod 5, as this is a convenient-arrangement, but spring 9, or other'means tending norinally toapply thebrake, may be carried in any other convenient place and may act on the brake bands. directly or on any part of the brake controlling mechanism provided that its force tends. to apply the brakes. 11 is a hole or port to which pipe 2 is connected and through which fluid under pressure from pump 3 enters cylinder 1 and forces piston 5 to the right, thereby overcoming the force of spring 6 and holding the car brakes Ofl w I 12 isa passage or port in cylinder 1 through which the fluid escapes'when the brake is applied and which is controlled by relief valve 13, the pressure in cylinder 1 being 'propor 1 tional to the strength and length of a spring e0 14 which tends to hold valve 13 on its seat. The exhausted fluid escapes through a hole orport 15 which, if desired, may be connected y a pipe 16 to an oil pump. 17 is a brake operating lever pivoted at 18 and rocked about pivot 18 in a clockwise direction by the spring 19 whichis stronger than, and thus overcomes, spring 14; and rocked about pivot 18 in a counterclockwise direction by manual pressure on the pedal 20 on the upper end of lever 17. 21 is a plunger mounted in a bore in cap 22- and having a head 23 integral therewith or rigidly fastened thereto. The upper end of plunger 21 acts as a stop ton-limit the clockwise movement of lever 17 and the lower end presses on the disk or washer 24 which acts as an abutment for spring 14.

. The strength of spring 14 when plunger 21 is down with head 23 pressing on cap 22 is so proportioned that the fluid pressure in cylinder 1 is sutficient to force piston 5 fully to the right against spring 9 and hold the brakes OE and the length and strength of spring 10 are so proportioned that when plunger 21 is fully up, that is when lever 17 is in its extreme counterclockwise position, there, is practically no super-atmospheric ressure in cylinder 1 and spring 9 will then orce piston 2 to the left and thus apply the car brakes. I

The operation of the device is as follows: Starting with the position shown in Figure 1 and with the fluid pressure in cylinder 1 at a maximum and the car brakes forced ofl; the operator, desiring to stop the car, presses on the pedal 20 rocking the lever 17 in a counterclockwise direction, thus relieving the pressure on spring 14 and reducing the fluid pressure in cylinder 1 by the desired amount.

Spring 9 then forces pistn5 to the left until equilibrium is again established between the lessened fluid pressure on one side of the 1S- ten 5 and the spring pressure on the ot or side. It is thus evident that the position of piston 5 is dependent upon the position of lever 17.

A complete means of controlling thecar brakes when there is fluid pressure available to overcome the force of spring 9 is thus pro;

vided, but as the source of fluid pressure is usually a pump operated b the engine, pressure is not always availab e, as for example when the engine stalls on a hill in which case the brakes would go on and the car be sto ped' until the fluid pressure were restored, w 10b cannot always be done. To release the'brakes in such'a situation a lever vis provided, which is hinged at 26 and cooperating withcollar 8, which lever on being pushed to the left at the top will 'force piston'rod 6 to the right, compressin spring 9 and holding the erating lever 17.

- jection 29 will hold the brake oil until it is released, irrespective of whether there is fluid pressure available or not and the car may be towed or pushed, the braking being obtained by use of the emergency brake. It is evident .that the lever 25 might be put into engagement' with projection 29 and thus the fluid controlled brakes be put out of action unknown to the driver, in which case when the first occasion arose to apply the brakes the driver would naturally press on pedal 20 and expect the brake to operate, and if no provision were made to cause the release of lever 27 when the pedal 27 was pushed down, a serious accident might result.

This provision is obtained by the fact that the pro ection or stop 29 on brake operating lever 17 will only cooperate with and prevent the endof the arm- 27 from coming freely to the left when the lever 12 is in its extreme clockwise position, so that when the driver presses on pedal 20 and rocks lever 17 in the normal way to apply the brake he will thereby automatically trip arm 27 ofi stop 29 and release the lever 25 to permit the spring 6 to apply the brakes. The outer end of the lever 27 issupported in any suitable manner, as by means of the pivot pm 18.

I claim: 1. The combination with a brake, of means tending to. applz the brake, fluid pressure means norma ly lding the brake out of action, a brake operating lever, manually operable-means for holding saidlbrakeapplying -.1

means out of action if said fluid pressure means be inoperative, and means actuated by said brake operating lever for releasin sa-ld manually operable means when said rake operatin lever is moved to apply the brake.

2. Bra e control means comprising a cylinder, a iston inv said 0 linder, a rod connected tosaid cylinder an passin through one endwall of said cylinder, a fluid inlet in the other endlof said cylinder, spring means con- .stantlytending to urge said piston toward said inlet, a fluid outlet communicating with the end of the cylinder adjacent said inlet, a valve interposed betweensaid inletand outlet, a spring tending to close said valve, 9. plunger coactingwith said valve, a manually operated lever engaging said plunger, a

stronger spring urging said lever to cause it normally to compress said valve closing spring. 3. rake control means as claimed in claim 2, comprising also a pivoted manually operated arm engaging said piston rod, a projecmember pivoted to said arm and coacting with said projection to hold the brake ofi positively, but arrangedto be automatically disengaged from said projection when the UNSELL B. JACKSON.

tion on the manually operated lever, and a v 

